NBN Co has told a parliamentary hearing that it does not have a uniform strategy of connecting apartment buildings to the National Broadband Network (NBN).

NBN Co has told a parliamentary hearing that it does not have a uniform strategy of connecting apartment buildings to the National Broadband Network (NBN).

Ralph Steffens, chief operating officer at NBN Co, told a Joint Committee on the National Broadband Network that it was still working on its strategy for how to connect apartment buildings, which NBN Co calls multi-dwelling units (MDUs), to the NBN.

"We are working on this. There is no right answer to this. Every MDU looks different -- there is not one method of connecting MDUs and installation methodology evolves rapidly. Therefore, what we do today can change over time because there will be no efficient way of doing this," he said.

"[But] we are connecting MDUs today."

NBN Co told Computerworld Australia 189 MDUs have been completed and work is under way on another 200 MDUs. "Over the course of the rollout we expect to connect over 400,000 MDUs, including building[s] constructed over the next 10 years," a spokesperson said.

NBN Co classifies an MDU as a premise where two or more homes joined by a common wall or property boundary and managed by a body corporate, with MDUs making up around one-third of premises to receive the NBN via fibre.

Steffens told the hearing this can include a block of town houses. For example, a set of 10 town houses could potentially be labelled an MDU.

The committee was also told that in situations where an apartment building's body corporate does not agree to an NBN connection and declared "frustrated", NBN Co will move on.

"If the body corporate doesn't agree, we will obviously try and convince them to accept the installation. If ultimately the body corporate says no, we declare the building frustrated and move on..." said Mike Quigley, chief executive at NBN Co.

"We anticipate not a large number of MDUs to be declared frustrated. We think most body corporates would say 'this is a good thing -- go ahead and install it'. Now we may have some -- we expect there will be some..."

Steffens told the committee so far no MDUs had been declared frustrated.

The Department of Broadband, Communications and the Digital Economy has previously stated that MDUs are typically cheaper to roll out fibre to than single-dwelling units.

"Being lower cost and typically found in higher-density areas, most MDUs are likely to fall within the fibre footprint of the NBN and are also likely to be commercially attractive to NBN Co," it said.

"Providing FTTP coverage to MDUs is therefore important to NBN Co both for its business case and for meeting its FTTP coverage requirement."

However, the report stated there were several challenges of connecting MDUs to the NBN. For example, engaging with MDU entities, such as the body corporate, which can result in delays.

"Delays in the roll-out schedule or the need for roll-out teams to revisit areas can increase the cost of the roll-out," it stated.